Electron Transport in TiO2−x at Intermediate Temperatures 300 K < T < 1500 K

A critical analysis is made of the previous works on conductivity measurements and electron motion in TiO2 (rutile) which show that electronic mobility whatever the direction of current is a decreasing function of the temperature. In order to find an accurate expression of the perpendicular mobility, a fit of Iguchi's results is attempted. Although a good fit is obtained with a defect model based on ionized oxygen vacancies and a quasi-constant mobility, this is inconsistent with previous works. Furthermore simultaneous conductivity and Seebeck effect measurements are performed in order to eliminate electronic concentration and sift out the temperature variation of the mobility and of the transport term of thermopower. This yields a mobility governed by acoustic phonon scattering within a very large range of temperatures. An influence of optical phonon scattering may occur but only at high temperatures.